Mobile phones and many other small and medium sized OLED screens use R, B sub-pixel display mode (FIG. 1). In order to improve the production yield, some functional layers are often designed as shared layers, reducing fine metal mask (FMM) usage. Hole transporting layer often uses a shared layer, and shared hole transporting layer may consist commercially available materials. The commercially available hole transporting layer materials may include a molecular structure as,
(e.g. EP-721935). However, such materials show higher longitudinal mobility rate, but the lateral mobility rates are not very high. There will be no occurrence of crosstalk between pixel. Patent CN103108859 discloses a material structure
wherein the material has a good solubility, and a higher mobility rate than the EP-721935 type. There are several problems in the current technologies of hole transporting materials. First, the material solubility is not good, which will lead to a worse cleaning effect of Mask for evaporation during mass production. Second, the material mobility rate is too low, which will lead to an excessive overall voltage of devices. Third, the mobility rate of the material, especially the lateral mobility rate of the material, is too high, leading to crosstalk of adjacent pixels.
The mobility rate of the commercially available material in EP-721935 falls within the acceptable range, and no crosstalk will occur. However, the solubility thereof is not very good. The solubility of the commercially available material in CN103108859 is acceptable, but too high mobility rate leads to lateral leakage current to form crosstalk. Accordingly, there is a need to develop a hole transporting material having a suitable mobility rate without the occurrence of crosstalk between adjacent pixels.